1. Field of the Invention
This invention relates to powder fusion welding and more particularly to a splitter for a fluid and powder flow stream that enables a single stream of such powder flow to become several streams.
2. Description of the Related Art
With the increased use of lasers to provide powder fusion welding, articles can be constructed having net shape or near-net shape. This provides significant advantages as compared to casting or other component-making processes.
In a powder fusion process, fusion material is fed to the active focus point of the welding tool, usually a laser or other energy source. The powder may contain a variety of different substances including particulate metals and plastics. Generally, a reservoir of fusion powder is used to deliver the fusion powder to the welding torch. In some cases, the powder flow stream must be split into several substreams in order to provide better powder flow to the welding torch through several different flow trajectories. Otherwise, separate, independent, and generally-expensive feed powder reservoirs and systems would be used where multiple feed powder lines are needed. The fusion powder is generally delivered to the welding torch by means of pressurized gas, or fluid, such as an inert or non-reactive gas such as helium, argon or nitrogen.
While the art of providing nozzles for laser welding torches is well developed, the art of powder flow splitters is less developed. Some of the problems arising with the splitting of fusion powder flow relate to aberrations or flaws within the flow lines or system design, which can cause the powder to stick and resist the forward travel of the powder. Over time, particles may collect at a certain point and accumulate into a blockage. Additional problems may arise from the generation of static electricity from interparticle friction as well as the loss of downstream pressure during the powder flow splitting process.
Additionally, in one known splitter design, there is no adjustability of the output flow streams to vary powder and fluid flow between the various output flow streams.
The conventional splitter has internal recessed apertures set apart from a main block where the channels then diverge in an outward configuration. The splitter is generally in two parts which are held together by a bolt or screw and there can be some relative movement due to the loose fit between the incoming powder flow cap and the outgoing splitter feed channels.
Under certain circumstances, this powder feed splitter is subject to clogging which dramatically interferes with the operation of any process relying upon the split powder feed. Once the splitter begins to clog, powder flow is reduced and if diminished too much, the entire operation must be stopped and the splitter cleaned and the clog removed. This may involve dismantling the splitter and interrupting the laser fusion process that is dependent upon the split powder flow.
Additionally, no gas pressure is used in the conventional splitter configuration, above, to enhance powder flow. Gravity flow alone serves as the means by which its powder feed is split into separate powder flow lines. Additionally, because the powder feed output lines do not travel outwardly straight from the powder feed splitter, but instead radiate outward at an angle, additional clogging may occur in the powder flow lines. Due to both the loose fit between the powder feed splitter halves and the inability to reliably and selectively control the incoming powder flow within the powder splitting portion, it is difficult to repeatably align and adjust such a previously-known powder feed splitter.
In view of the foregoing disadvantages present in the art, there is a need for an improved powder flow splitter that reduces clogging and/or allows adjustability and/or enhances or overcomes gravity flow with pressurized fluid and powder flow. The present invention solves one or more of these disadvantages.